Raintree Cat Condos The rear panel and the side panels are constructed of 3/4” fiber board that has a thermally fused melamine surface. The doors and both main floors are constructed of PVC board that has a high pressure laminate surface bonded to it. The shelves are constructed of 3/4” PVC sheet. Windows in doors and rear panels are 1/4” tempered glass. Door glass will have six holes for ventilation purposes. Units are sealed with a thermoset urethane adhesive. close window